Strut-and-Tie Model for Punching Failure of Column Footings and Pile Caps.

A design method for spread footings and pile caps is presented. The model is in principle based on the strut-and-tie concept, but with the strut dimensions defined by compatibility conditions and therefore not possible to manipulate by the designer. Due respect is paid to the size effect--that is, the decreasing strength with increasing member size--which seems to be disregarded by common strut-and-tie methods. Comparison with test results of column footings and four-pile caps in the literature demonstrates that brittle punching failure as well as yielding and brittle cracking failure can be predicted with very good accuracy. [ABSTRACT FROM AUTHOR]